and in consequence \(H_i\)  are generators of diffeomorphisms \(\widetilde{x}^i=x^i+\delta x^i\)  [1]}
\(\left[h_{ij},i\int _{\partial M}H_{a}\delta x^a d^3x\right]&=&-h_{ij,k}\delta x^k-h_{kj}\delta x^{k}_{~,i}-h_{ik}\delta x^{k}_{~,j}~~,\\\left[\pi _{ij},i\int _{\partial M}H_{a}\delta x^a d^3x\right]&=&-\left(\pi _{ij}\delta x^k\right)_{,k}+\pi _{kj}\delta x^{i}_{~,k}+\pi _{ik}\delta x^{j}_{~,k}~~,\) 
